* {
  margin: 0;
  padding: 0;
}

*,
*::before,
*::after {
  box-sizing: inherit;
}

html {
  box-sizing: border-box;
  /* Set font size for easy rem calculations
   * default document font size = 16px, 1rem = 16px, 100% = 16px
   * (100% / 16px) * 10 = 62.5%, 1rem = 10px, 62.5% = 10px
  */
  font-size: 62.5%;
  scroll-behavior: smooth;
}

/* 1200px / 16px = 75em */
@media (max-width: 75em) {
  html {
    font-size: 60%;
  }
}

/* 980px / 16px = 61.25em */
@media (max-width: 61.25em) {
  html {
    font-size: 58%;
  }
}

/* 460px / 16px = 28.75em */
@media (max-width: 28.75em) {
  html {
    font-size: 55%;
  }
}

body {
  font-family: 'FangSong';
  font-size: 1.8rem;
  font-weight: 400;
  line-height: 1.4;
}

h1,
h2 {
  font-weight: 700;
  text-align: center;
}

h1 {
  font-size: 6rem;
}

h2 {
  font-size: 4.2rem;
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
}

img {
  display: block;
  width: 100%;
}

.nav {
  display: flex;
  justify-content: flex-end;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 10;

  .nav-list {
    display: flex;
    margin-right: 2rem;

    a {
      display: block;
      color: white;
      font-size: 2.2rem;
      padding: 2rem;
    }
  }
}

@media (max-width: 28.75em) {
  .nav {
    justify-content: center;
  }

  .nav-list {
    margin: 0 1rem;
  }

}

#ayi {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100vh;
  background: linear-gradient(235deg, #8e9eab 0%, #eef2f3 100%);

  h1 {
    animation: h1a 1s cubic-bezier(0.550, 0.085, 0.680, 0.530) both;
  }

  @keyframes h1a {
    0% {
      -webkit-filter: blur(12px);
      filter: blur(12px);
      opacity: 0;
    }

    100% {
      -webkit-filter: blur(0px);
      filter: blur(0px);
      opacity: 1;
    }
  }

  a {
    color: #000000;
    transition: all 0.3s ease-in;

    &:hover {
      color: white;
      // font-size: 6.5rem;
    }
  }

  // p {
  //   font-size: 3rem;
  //   font-weight: 200;
  //   font-style: italic;
  //   margin: 1rem auto 3rem;
  // }

  button {
    margin-top: 5rem;
    position: relative;
    padding: 1.9rem 3.6rem;
    display: block;
    text-decoration: none;
    text-transform: uppercase;
    overflow: hidden;
    border-radius: 4rem;
    border: none;
    background-color: rgba(142, 158, 171, .5);

    span {
      position: relative;
      color: rgb(0, 0, 0);
      font-family: Arial;
      letter-spacing: 8px;
      z-index: 1;

    }

    .btn {
      position: absolute;
      top: -80px;
      left: 0;
      width: 100%;
      height: 200px;
      background: #acb8c1;
      box-shadow: inset 0 0 50px rgba(0, 0, 0, .5);
      transition: .5s;

      &::before,
      &::after {
        content: '';
        width: 200%;
        height: 200%;
        position: absolute;
        top: 0;
        left: 50%;
        transform: translate(-50%, -75%);
        background: #fff;
      }

      &::before {
        border-radius: 45%;
        background: rgba(20, 20, 20, 1);
        animation: animate 5s linear infinite;
      }

      &::after {
        border-radius: 40%;
        background: rgba(20, 20, 20, .5);
        animation: animate 10s linear infinite;
      }
    }

    @keyframes animate {
      0% {
        transform: translate(-50%, -75%) rotate(0deg);
      }

      100% {
        transform: translate(-50%, -75%) rotate(360deg);
      }
    }
  }



}

#demo {
  width: 100%;
  background-color: black;
  padding: 5rem 2rem;

  .demo-title {
    max-width: 540px;
    margin: 5rem auto;
    padding: 2rem;
    font-size: 2.5rem;
    color: #fff;
    border-bottom: 1rem solid rgb(110, 110, 110);
  }

  .content {
    display: grid;
    grid-template-columns: repeat(2, minmax(320px, 1fr));
    grid-gap: 4rem;
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    margin-bottom: 6rem;

    .box {
      text-align: center;
      color: #8e9eab;

      .box-img {
        width: 100%;
        height: 40rem;
        object-fit: contain;
      }

      .box-font {
        font-size: 3rem;
        font-weight: 700;
        margin: 2rem;
        animation: text-focus-in 1s cubic-bezier(0.550, 0.085, 0.680, 0.530) both;
      }

      @keyframes text-focus-in {
        0% {
          -webkit-filter: blur(12px);
          filter: blur(12px);
          opacity: 0;
        }

        100% {
          -webkit-filter: blur(0px);
          filter: blur(0px);
          opacity: 1;
        }
      }


      transition: transform .3s ease-in;

      &:hover {
        transform: scale(1.2);
        z-index: 8;
      }
    }
  }

  @media (max-width: 30.625em) {
    #demo {
      padding: 5rem 1rem;
    }

    .demo-title {
      font-size: 3rem;
    }

    .content {
      grid-template-columns: 1fr;

      .box {

        .box-img {
          height: 20rem;
        }

        .box-font {
          font-size: 2.5rem;
        }
      }
    }
  }

}

#more {
  width: 100%;
  background: linear-gradient(45deg, #92B6A1 27%, #1B6F52 67%);
  height: 100vh;
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;

  h2 {
    color: #eef2f3;
  }

  p {
    margin: 4rem auto;
    font-size: 2.5rem;
    font-style: oblique;
    font-weight: 600;
  }

  .csdn {
    border: none;
    background: none;
  }

  .csdn span {
    padding-bottom: 7px;
    letter-spacing: 4px;
    font-size: 10px;
    padding-right: 15px;
    text-transform: uppercase;
  }

  .csdn svg {
    transform: translateX(-8px);
    transition: all 0.3s ease;
  }

  .csdn:hover svg {
    transform: translateX(0);
  }

  .csdn:active svg {
    transform: scale(0.9);
  }

  .hover-underline-animation {
    position: relative;
    color: black;
    padding-bottom: 20px;
  }

  .hover-underline-animation:after {
    content: "";
    position: absolute;
    width: 100%;
    transform: scaleX(0);
    height: 1.5px;
    bottom: 0;
    left: 0;
    background-color: #000000;
    transform-origin: bottom right;
    transition: transform 0.25s ease-out;
  }

  .csdn:hover .hover-underline-animation:after {
    transform: scaleX(1);
    transform-origin: bottom left;
  }

}

footer {
  background-color: rgb(191 201 208);
  text-align: center;
  padding: 2rem;
}